As title suggests, I'm curious to know if an upper chambered in .50 BMG much like those made for the mil-spec AR-15 lower exists, only one made to mate with the most popular of the AR-10 platforms, namely the SR-25/DPMS GI/AR-308 lower receiver.
Many have suggested this to be superior to the current art of the AR-15 platform, due to the buffer tower being a probable suspect for crack formation over repeated use of the high-report .50 BMG round in an upper of its size mated to a much lighter (and smaller) lower.
Any examples out there of what I'm describing?